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Sandakan, Malaysia

Edwards D.P.,University of Leeds | Edwards D.P.,Princeton University | Edwards D.P.,James Cook University | Backhouse A.R.,University of Leeds | And 3 more authors.
Journal of Insect Conservation | Year: 2012

The inclusion of carbon stock enhancements under the REDD+ framework is likely to drive a rapid increase in biosequestration projects that seek to remove carbon from the atmosphere through rehabilitation of degraded rainforests. Concern has recently been expressed, however, that management interventions to increase carbon stocks may conflict with biodiversity conservation. Focusing on a large-scale rainforest rehabilitation project in northern Borneo, we examine the broad impacts of selective logging and subsequent carbon enhancement across a wide range of invertebrate fauna by comparing the abundance of 28 higher-level taxa within two separate rainforest strata (leaf-litter and understorey) across unlogged, naturally-regenerating and rehabilitated forest. We additionally assess changes in functional composition by examining responses of different feeding guilds. Responses of individual taxa to forest management were idiosyncratic but logging resulted in more than a 20% increase in total invertebrate abundance, with fewer than 20% of taxa in either stratum having significantly lower abundance in logged forest. Rehabilitation resulted in a marked reduction in abundance, particularly among leaf-litter detritivores, but overall, there were much smaller differences between unlogged and rehabilitated forest than between unlogged and naturally regenerating forest in both total invertebrate abundance and the abundances of different feeding guilds. This applied to both strata with the exception of understorey herbivores, which were more abundant in rehabilitated forest than elsewhere. These results support previous data for birds suggesting that carbon stock enhancement in these forests has only limited adverse effects on biodiversity, but with some impacts on abundance within particular guilds. © 2011 Springer Science+Business Media B.V. Source

Edwards F.A.,University of Leeds | Edwards D.P.,University of Sheffield | Edwards D.P.,James Cook University | Larsen T.H.,Wildlife Conservation Society | And 6 more authors.
Animal Conservation | Year: 2014

Forests in Southeast Asia are rapidly being logged and converted to oil palm. These changes in land-use are known to affect species diversity but consequences for the functional diversity of species assemblages are poorly understood. Environmental filtering of species with similar traits could lead to disproportionate reductions in trait diversity in degraded habitats. Here, we focus on dung beetles, which play a key role in ecosystem processes such as nutrient recycling and seed dispersal. We use morphological and behavioural traits to calculate a variety of functional diversity measures across a gradient of disturbance from primary forest through intensively logged forest to oil palm. Logging caused significant shifts in community composition but had very little effect on functional diversity, even after a repeated timber harvest. These data provide evidence for functional redundancy of dung beetles within primary forest and emphasize the high value of logged forests as refugia for biodiversity. In contrast, conversion of forest to oil palm greatly reduced taxonomic and functional diversity, with a marked decrease in the abundance of nocturnal foragers, a higher proportion of species with small body sizes and the complete loss of telecoprid species (dung-rollers), all indicating a decrease in the functional capacity of dung beetles within plantations. These changes also highlight the vulnerability of community functioning within logged forests in the event of further environmental degradation. © 2013 The Zoological Society of London. Source

Woodcock P.,University of Leeds | Edwards D.P.,James Cook University | Newton R.J.,University of Leeds | Edwards F.A.,University of Leeds | And 3 more authors.
Naturwissenschaften | Year: 2012

Nitrogen isotope signatures (δ 15N) provide powerful measures of the trophic positions of individuals, populations and communities. Obtaining reliable consumer δ 15N values depends upon controlling for spatial variation in plant δ 15N values, which form the trophic 'baseline'. However, recent studies make differing assumptions about the scale over which plant δ 15N values vary, and approaches to baseline control differ markedly. We examined spatial variation in the δ 15N values of plants and ants sampled from eight 150-m transects in both unlogged and logged rainforests. We then investigated whether ant δ 15N values were related to variation in plant δ 15N values following baseline correction of ant values at two spatial scales: (1) using 'local' means of plants collected from the same transect and (2) using 'global' means of plants collected from all transects within each forest type. Plant δ 15N baselines varied by the equivalent of one trophic level within each forest type. Correcting ant δ 15N values using global plant means resulted in consumer values that were strongly positively related to the transect baseline, whereas local corrections yielded reliable estimates of consumer trophic positions that were largely independent of transect baselines. These results were consistent at the community level and when three trophically distinct ant subfamilies and eight abundant ant species were considered separately. Our results suggest that assuming baselines do not vary can produce misleading estimates of consumer trophic positions. We therefore emphasise the importance of clearly defining and applying baseline corrections at a scale that accounts for spatial variation in plant δ 15N values. © Springer-Verlag 2012. Source

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